Effect of ScAl/sub 3/ phase dispersity on hardening of Al-6. 3 pct Mg-0. 21 pct Sc alloy

The relative contributions of disperse coherent ScAl/sub 3/ segregations and of the substructure to the hardening of an aluminum alloy containing 6.3 pct Mg and 0.21 pct Sc are evaluated quantitatively. It is shown that the extent of substructure hardening is independent of the dispersity of coherent ScAl/sub 3/ particles and, consequently, of the homogenizing treatment. The contribution of coherent ScAl/sub 3/ segregations less than 20 nm in diameter to the hardening of the alloy significantly exceeds that of substructure hardening. 9 references.